A currently suggested driving assisting apparatus includes a front side assisting apparatus for a vehicle and a rear side monitoring apparatus for a vehicle. Here, a rear side assisting apparatus for a vehicle is an apparatus installed for preventing a minor collision between a rear object existing in a field of view, that is, a blind spot, which cannot be confirmed through a room mirror or a side mirror when a driver reverses a vehicle, and a vehicle. That is, the rear side assisting apparatus for a vehicle is an apparatus for detecting a rear object, and generating an alarm when a distance between the detected rear object and the vehicle is within a predetermined distance. Further, similar to the rear side assisting apparatus for a vehicle, the front side assisting apparatus for a vehicle is an apparatus for detecting a front object, and generating an alarm when a distance between the detected front object and the vehicle is within a predetermined distance.
However, research on an apparatus, to which a technique for assisting in a lane change while a vehicle travels is applied, considering a currently suggested driving assisting apparatus is inadequate. Particularly, a field view problem generated due to a lane change while the vehicle travels has a considerably higher risk of an accident than a field view problem generable at a front side and a rear side of the vehicle. Accordingly, a technique for assisting in a lane change while a vehicle travels, and notifying a driver of a danger according to the lane change in advance has been needed.
In the meantime, a technique for detecting an obstacle existing on a driving lane of a vehicle has been disclosed as a prior art, and particularly, the technique obtains an image of a front side of a vehicle by using an outside camera for photographing a front side, analyzes the image of the front side of the vehicle, and recognizes whether an obstacle exists on a driving lane. In this case, it is impossible to detect whether a travelling vehicle, not an obstacle, moves, and particularly, it is impossible to help a driver to recognize a danger of an accident occurable when two or more vehicles (for example, vehicles travelling the first lane and the third lane) simultaneously change lanes toward the same lane (for example, the second lane) in advance.